Heating apparatus



G. SCHWAB Aug. 12, 1930.

HEATING APPARATUS Original Filed Dec. 24, 1925 INVENTOR.

Patented Aug. 12, 1930 UNITED STATES PATENT OFFICE HEATING APPARATUSApplication filed December 24, 1925, SerialNo. 77,477. Renewed February8, 1929.

This invention is an instantaneous heating course, be of substantiallythe same cross sectional area as the inlet and outlet pipes of theheater and generally are larger to compensate for relatively largefriction losses. Ittherefore follows that, when the heating operationstarts, it is necessary to heat up a relatively large body of waterbefore hot v water can be continuously supplied. The tube and chamberheaters heretofore referred to are all open to the same objection, thestorage of water invariably being of a sufliciently great quantity toappreciably retard the initial flow of hot water.

With these and other considerations in mind, the object of the presentinvention is, primarily,'to provide a truly instantaneous heater, i. e.,one wherein the capacity to supply hot gas or liquid will immediatelyfollow the application of heat.

I have discovered that this result can be f obtained by passing thefluid to be heated through an annular space in an axial direction and soproportioning said space that its cross sectional area will, inthe main,be substantially the same as the cross sectional area of the pipethrough which the heated fluid is discharged from said space. Inpractice, the annular heating space is formed within the hollow wall ofa bell-like structure which is both internally and externally heated,thehottest combustion gases striking thethe fluid or medium tobecontainer holdin heated at the point of discharge of such fluld ormedium. This arran ement provides relatively greatsuperficial eatingsurfaces between which the fluid to be heated is contained insubstantiallythe form of a film. As a result, the heating of the fluidis instantaneous.

Another object of the invention is to provide efiicient means forsupplying and controlling the application of heat to the bell: likestructure. In carrying out this phase of the invention, the bell ishoused within a suitable casing which is closed except for an openingadmitting the fuel burner and secondary combustion air, the admission ofwhich latter may be made regulatable by a shutter arrangement. Arefractory or metal mantle or sleeve is secured in the bottom opening,forming a combustion chamber for the heating fuel, which, in most cases,will be any available fuel gas, which refractory or metal mantle orsleeve extends into the interior of the bell.

When the burner is in operation, the mantle becomes highly heated, sothat complete combustion of the fuel may take place as no chillingaction of the gas can take place during theprocess of combustion proper.The 7 fuel becomes fully oxidized within the mantle and bell, and thehot' waste products of combustion pass beneath the lower edge of thebell and upwardly around its exterior to be discharged through theoutlet to a suitable stack, or otherwise disposed of in such manner sothat the remaining heating energy of the OE gases may be usefullyemployed. The supply of fuel is preferably automatically controlled by athermostatic regulator acted upon by the outgoing heated fluid. Auniform heating is thereby rendered possible.

The apparatus is thus rendered thoroughly eflicient for the carrying outof its intended functions.

Features of the invention, other than those t adverted to, will beapparent from the hereinafter detailed description and claims, when readin conjunction with the accompanying drawings.

The accompanying drawing illustrates a practical embodiment of theinvention, but the construction therein shown is to be understood asillustrative, only, and not as defining me the limits of the inventlon.ll

Figure 1 is a central section of heating apparatus embodying the presentinvention.

Figure 2 is a section on the line 22 of Figure 1.

Referring to the drawings, 1 designates a suitable casing provided atthe center of its bottom with an opening 2. Mounted in the opening 2 andextending a short distance into the casing is a tubular sleeve 3 to theupper portion of which is secured a laterally extending spider 4. Thespider carries at its periphery an annular channel 5, which forms asupport for a bell-like member 6. I The belllike member seats in thechannel 5. It may be constructed of any suitable material provided thatits wall is hollow to form within said wall a heating space 7. An inletpipe 8 leads into the space 7 near the lower edge of the bell and anoutlet pipe 9 leads out of the upper portion of said space, the flowcapacity of the outlet pipe being desirably sub stantially the same asthat of the space 7. The fluid to be heated enters the heating spacethrough the pipe 8 and leaves it through the pipe 9 and it will be notedthat the latter pipe is of somewhat larger cross sect-ion than theformer in order to provide against back pressure and friction losses andto take care of expansion of the fluid during heating.

In the horizontal plane of the pipe 8, the inner and outer walls of thespace 7 are bulged slightly to form a header 10 and the fluid fedthrough the pipe 8 enters this header and passes upwardly through thespace 7 to be discharged through the pipe 9.

That portion of the space 7 above the header 10 is desirably of annularshape having a flow capacity substantially equal to the flow capacity ofthe outlet pipe 9. Since the outlet pipe 9 is not unduly large, itbecomes apparent that the space 7 is relatively constricted, soconstricted in fact that fluid pass ing through said space issubstantially filmed, and it is thus susceptible to a most eflicientheating particularly if heat for this purpose is applied to both theexterior and interior of the bell. The [source of heat consists in aburner 11 which extends into the sleeve 3 and is supplied with eitherliquid or gaseous fuel, through pipe 12. For the purpose ofillustration, the gas burner is shown in the drawings.

Seated on top of the sleeve 3 is a mantle 14 of refractory or metalmaterial, this mantle being coaxial with the sleeve 3 and extending wellup into the bell. With this arrangement, it will be apparent thatfuelissuing from the burner and ignited in the mantle will result in aflame flowing upward- 1y through the mantle and this flame will, inpractice, heat the mantle to a state of incandescence. The injectionaction of the flame in the mantle will serve to draw air into the bottomof the mantle through the sleeve 3 and said air will oxidize the fuel toproduce complete combustion. The flame issuing from the top of themantle enters directly into the interior of the bell and is deflecteddownwardly through the bell around the outside of the mantle and passesunder the lower edge of the bell and upwardly around the exteriorthereof. The waste products of combustion leave the casing through theoutlet 13 at the top thereof and may desirably be directed to asuitablestack.

During the chemical process of combustion, the combustible fuel does notcome into contact with cool surfaces, so that the likelihood of unburnedgases reaching the stack with the waste products of combustion ispractically nil. The hottest point of burning is at the top of theinterior of the bell adjacent the point of discharge of the fluid beingheated and for this reason the discharge portion of the header or domethereof might be termed a squeezer dome, since here the fluid to beheated may be caused to pass through a minimum area even through aslightly reduced area from the area of the annular film space whilebeing subjected to the most intense heat application; the crosssectional area of the dome, taken normal to the direction of water flowis so reduced that the flow capacity of the dome portion issubstantially the same as that of the annular body portion of theheating chamber.

As hereinbefore stated, the products of combustion pass downwardlyinside of the bell thus applying during such downward passage a countercurrent system with respect to the medium to be heated withcorrespondingly high heating efliciency and during the subsequent upwardpassage of the waste products exteriorly of the bell. The

heat therein contained is utilized to further heat the medium in saidbell. In practice, the casing 1 is preferably insulated at 16 for thepurpose of reducing heat losses by radiation to a practical minimum.

Importance is attached to the outward bulging of the walls ofthe space 7as seen in Figure 1 as at 10. The water is fed in in the form of a thinfilm to areservoir formed by thisbulge in the walls of the jacket. Thisannular reservoir receives the cold water and stores it sufliciently totemper the heat of the jacket at all times, so that'it can never besufliciently overheated to cause an explosion or tearing apart of thematerials. Further- 'more, this water which is at all times contained inthe annular bulge, is fed in the form of a thin film from the point oflowest heat progressively to the point of greatest heat and it thereforefollows that the heating is progressive, constant, and eflicient andthere is no counter flow of cooling liquid such as would be present ifthis expansible bulge were not present. By so bulging the walls of thejacket and positioning this bulge below the lower edge, there is more orless of an elastic thermostatic control device 15, the operating unit 15of which extends into the outlet pipe 9. Any suitable control unit maybe employed in this connection, but in any event, it will so regulatethe feed of fuel as to produce substantially uniformheating.

The heating apparatus of-this invention may be employed to heat eitherliquids or gases, it being understood, however, that relative sizes ordimensions of the parts would of course be proportioned for theparticular medium to be operated upon, as will be apparent to thoseskilled in the art.

Modifications of the invention will appear to those skilled in the artand the invention is therefore to be understood as fully commensuratewith the appended claims.

Having thus fully described the invention, what I claim as new anddesire to secure by Letters Patent is:

1. A fluid heating apparatus embodying a double walled bell, the innerand outer walls of which are closely spaced apart at both the sides andtop of the bell to form an intermediate fluid heating space for fluid,an annular bulged portion extending about the bell adjacent the openlower end thereof and providing for expansion and contraction, an inletleading into said bulged portion, and an outlet at the apex of the belland a casing enveloping the said bell and spaced therefrom,

the flow capacity of the fluid space being substantially equal to theflow capacity of the V outlet, and means'for directing a hot blast ofincandescent fuel into the interior of the bell through the open bottomthereof to impinge fuel thence out through the bell and over the outersurface thereof, whereby the fluid assing between the inner and outerwalls 0 the bell is squeezed through a minimum permissible area at theapex of the bell and there subj ected to the most intense heatapplication.

2. In an instantaneous water heater, in combination, a pair of domelikeshell members placed one around the other. to define a jacket in whichthe water is heated, means for introducing water at the lower end of thejacket, and a discharge conduit leading from the apex of the dome of thejacket to carry off the heated water, the cross sectional areas of thedischarge conduit and the jacket being so proportioned that the flow caacity of the discharge conduit is substantia y equal to the flowcapacity of the jacket.

expansion and contraction due to temperature variations. 7

4. In an instantaneous water heater, in combination, a pair ofshell-like members having cylindrical body portions placed one aroundthe other to provide a water space of substantially uniformcross-section in the body portion, means for introducing water near thebottom of said "body portion, each member bein provided with a domeliketop wall, means or discharging water from the apex of the dome, such topwalls being'situated so close together that the cross-section takennormal to the direction of water flow of the dome portion of the watercirculating space is less than the cross-section taken normal to thedirection of water flow of the body portion of the water circulatingspace, the

dome portion havin substantially the same flow capacity as the 0dportion.

In testimony whereo I have signed the foregoing specification.

GUSTAV SCHWA'B.

